Theunissen is a Dutch patronymic surname meaning "son of Theunis", a nickname for Anthonius.[1] People with this surname include:
Corneille Theunissen (1863–1918), French sculptor
Elriesa Theunissen (born 1993), South African cricketer
Gerald Theunissen (born 1933), American (Louisiana) politician and businessman
James Theunissen (born 1981), English cricketer
Marthinus Theunissen (1911-1983), South African sprinter
Michael Theunissen (born 1932), German philosopher
Nicolaas Theunissen (1867–1929), South African cricketer
Werner Theunissen (1942-2010), Dutch composer and musician
Theunisse
Gert-Jan Theunisse (born 1963), Dutch road racing cyclist
